As you might know, a learner's knowledge of grammar is different from actual practice, when finally speaking in real situations. In fact, in the real situation, many non-native speakers still get confused between the Be V+ingsentence("I am chatting") and the Present Simple sentence ("I chat"). They usually mix these up.

But you must remember the crucial difference, because it can make the meaning of your sentences wrong.

For example, imagine that you're talking to a kidin a swimming pool…

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(All the sentences in the dialogue below are right.)

Q: Are you sleeping?

A: No, I’m not sleeping!!!

Q: Do you sleep?

A: Yes, I sleep.

Q: Are you eating?

A: No, I’m not eating!!!

Q: Do you eat?

A: Yes, I eat.

Q: Are you wearing shoes?

A: No, I’m not wearing shoes!!!

Q: Do you wear shoes?

A: Yes, I wear shoes.

Can you see the difference?

In fact, non-native speakers often overuse the Present Simple sentence this way:

Q: Are you working?

A: Yes, I work. X

-- or –

Q: Will you join?

A: Yes, I join.X

Why? Why do non-native English speakers make this mistake?

Because the Present Simple is the easiest sentence to make in English. It's also the most natural and most convenient to use.

But as you can see, it’s a bad habit to use this sentence all the time. Because it has a different situation and it can actually make the meaning of your sentence strange.